Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Organ Systems > Limbic system & Basal Ganglia > Flashcards

Limbic system & Basal Ganglia Flashcards

1
Q

What structures are in the subcortical regions of the limbic system?

A

Hippocampus, amygdala, ventral striatum/nucleus accumbens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What structures are in the cortical regions of the limbic system?

A

Prefrontal, cingulate, insula, parahippocampal gyrus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the neuromodulatory pathway to the cortex involving NE and what does it control?

A

Projection from locus ceruleus (in pons) to cortex, brainstem, spinal cord, cerebellum (everywhere)
Attentional selectivity under stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the neuromodulatory pathway to the cortex and basal ganglia involving DA and what does it control?

A

Projection from ventral tegmentum (midbrain) to prefrontal cortex and basal ganglia
PFC projection promotes motivationally based behavior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the neuromodulatory pathway to cortical areas via serotonin and what does it do?

A

From raphe nucleus (medulla)

Mood; sleep-wake cycles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the neuromodulatory pathway to thalamus and extensive cortical areas via Ach and what does it do?

A

from Septum, nucleus basalis, diagonal band of Broca

Facilitate hippocampal and other cortical regions in memory and cognition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is the hippocampus?

A

3 layers near the surface of medial temporal lobe, bulges into lateral ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What afferent connections does the hippocampus have?

A

Afferents go into cortex (sensory, association, cingulate and PFC)–>parahippocampal gyrus in temporal lobe–>entorhinal cortex–>hippocampus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the functions of the hippocampus?

A

Encodes and consolidates episodic memories and projects to wide areas of cortex
Combines information from both ventral (what) stream and dorsal (where) stream to form episodic memories

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What efferent connections does the hippocampus have?

A

Efferents opposite from afferents

Contextual information is consolidated as memory into wide areas of cortex: prefrontal, temporal, parietal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is declarative memory?

A

Declarative memory: episodic (short-term context) and semantic (long-term, concepts)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the role of the hippocampus and vmPFC in forming and consolidating declarative memory?

A

I don’t know

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the stages of sleep and their EEG correlates?

A

REM: similar to waking, low amplitude, high frequency, 2nd half of sleep
non-REM: stages 1-4 increase in amplitude, decrease frequency, slow wave sleep (SWS), 1st half of sleep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the pathways that maintain wakefulness, and how do you fall asleep?

A

Ascending reticular pathways from brainstem to thalamus: cholinergic pontine pathways
From brainstem to cortex: monoaminergic pathways (NE, serotonin, DA), Cholinergic pathway from basal forebrain nucleus , orexin pathway from lateral hypothalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is sleep regulated by a circadian rhythm?

A

SCN projects light-dark phases to dorsal medial nuclei of hypothalamus (DMH)
With light, DMH promotes wakefulness by inhibiting VLPO (ventrolateral preoptic nucleus)
Cytokines (TNF, IL) disrupt the circadian sleep cycle during illness permitting sleep during the day for recovery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is memory consolidated in sleep?

A

Early nocturnal sleep (SWS stages 2-4): consolidate declarative and procedural memory
Late nocturnal sleep (REM): Final consolidation of memory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When does the reactivation of memory occur in sleep? When are they consolidated?

A

Declarative memories encoded by hippocampus are reactivated during SWS via decrease in ACh during SWS
Consolidated in several cortical areas for permanent storage during SWS and REM (enable insight from multiple similar episodes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What role does the septum have in ACh’s effect on cortical memory?

A

Septum regulates memory encoding in hippocampus via theta rhythms that separate periods of encoding of sensory stimuli and retrieval of episodic memory to avoid interference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What role does the diagonal band of Broca have in memory consolidation?

A

Nucleus basalis of Meynert (AKA band of Broca) projects to neocortex to facilitate in memory consolidation
Degenerates in Alzheimer’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What sleep-wake conditions optimize memory consolidation?

A

Memory reactivation during SWS mostly

REM sleep consolidation enables insight and correlations across multiple similar memories

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How is memory consolidation affected in Alzheimer’s disease?

A 
Inability to consolidate short term to long term memories
Nucleus basalis (Meynert) degenerates, leading to cognitive deficits, beta-amyloid plaque (extracellular)
Degeneration of cortex, cholinergic tracts
Neurofibrillary tangles (intracellular)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is memory consolidation affected in bilateral hippocampectomy?

A

Loss of memory consolidation

Only long term memory present (know how to lift a cup up but don’t remember what happened 1 minute ago)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How are emotional experiences manifested?

A

ANS: physiological, visceral
Behaviors: facial expressions
Subjective feelings: love, fear, hate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What role does the amygdala play in expressing emotions?

A

Take cognitive-emotion interactions and consolidate into memory (associate things with how you feel about them)
Perception and attention to both emotional valency (positive, negative) and intensity of personal and interpersonal emotions (with cortex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How do the efferent pathways from the amygdala generate affective/emotional attention?

A

Descending projection: go through hypothalamus which controls ANS for affective significance
Amygdala mediates expression of innate and learned fear, and anxiety
Increased heart rate, respiration, urination changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What types of facial expressions do the amygdala respond to and why?

A

Ambiguity: responds less to angry faces but more to fearful or surprised faces
Reacts more via fear to something you think might be danger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is emotional memory?

A

Conditioned fear via amygdala

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Describe conditioned fear and extinction and what brain areas generate them.

A

Conditioned fear is when sensory cues acquire significance via classical or Pavlovian conditioning
CS-US coupling of a sound and electric shock in quick sequence can generate amygdalar responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How is the amygdala regulated in its expression of emotional responses?

A

mPFC regulates the expression of emotions while hippocampus provides context to distinguish differences in threat

30
Q

What does it mean that the amygdala retrieves emotional memories unconsciously?

A

Masking of an emotional face (fearful, angry) within 15 ms doesn’t inhibit conditioned ANS response
Unconscious retrieval is mediated by auditory and visual association cortices, anterior insula, fusiform gyrus, pulvinar nucleus (subconscious pathway)

31
Q

Compare memories of emotions vs emotional memories.

A

Implicit emotional memories: Amygdala expresses emotions
Explicit memories about emotions: Hippocampus forms cognitive semantic and episodic representations of emotional situations that have happened

32
Q

How do high levels of NE and DA neuromodulation affect the relationship of prefrontal cortex and amygdala?

A

High NE and DA in response to stress inhibit PFC effects on amygdala, impairing working memory and attention, and strengthening fear conditioning in amygdala leading to anxiety

33
Q

What is meant by top-down and bottom-up control of the amygdala?

A

Top-down: PFC control, overrides compulsive behavior, slow, thoughtful regulation
Bottom-up: Sensory cortices, high NA, amygdala action especially during high stress, biasing toward habitual motor responses, reflexive emotional responses

34
Q

What effects do lesions of the vmPFC/OFC have on behavior?

A

Disinhibit amygdala
Unable to plan ahead, recognize consequences of actions
Inhibit emotional tendencies (Phineas Gage - aggressive)

35
Q

What effects do lesions of the amygdala have on behavior?

A

Inability to link past experiences to stimuli with important behavioral consequences
Don’t care about dangerous snake
Less aggression
Inappropriate sexual behavior
Inability to recognize facial expressions of strong emotions, especially fear
Visual, auditory or tactile agnosia

36
Q

Describe the location and some of the functions of the insula.

A

Deep to temporal lobe
Sends info to amygdala
Cue-processing (posterior) “what” and “where is it”
Context processing (anterior) “snake in a box” versus “snake in the wild”

37
Q

How does the insula relate to the amygdala?

A

In anxiety, amygdala has unconscious anticipatory reactivity while insula has conscious enhanced response to neutral stimulus when paired with aversive stimulus
Insula is stimulated by amygdala during negative states such as perceiving fearful faces, threat, expectation of painful stimuli
Interoceptive state: anxious individuals have an exaggerated prediction signal of a prospective aversive body state

38
Q

What is working memory?

A

Maintain and update task-relevant representations in mind; mental sketch pad; less dependence on environmental cues; activation of prefrontal and inferotemporal areas during delay of remembering a face

39
Q

What does the dlPFC do in working memory?

A

Executive control functions: formulate goals, inhibit inappropriate emotions, impulses, habits, conscious awareness, anticipate events in the near future

40
Q

What is the significance of the prefrontal cortex’s ability to sustain activity over long periods of time?

A

Working memory is sustained by NE and DA in dlPFC; strong connections to other parts of the brain to sustain attention

41
Q

What is the role of NE and DA in maintaining working memory? What happens in the dlPFC if there is excess of NE and DA?

A

NE and DA have complementary actions on dlPFC neurons: NE increases signals to preferred inputs, DA decreases responsivity to non-preferred stimuli
Excess = everything suppressed (a1)
Optimal (a2)

42
Q

What is basal ganglia?

A

Gray matter in the cerebral hemisphere that surround the thalamus

43
Q

What are the major constituents of the basal ganglia?

A 
Caudate
Putamen
nucleus accumbens
globus pallidus
subthalamic nucleus
substantia nigra, VTA
44
Q

What is the striatum?

A

Caudate plus putamen

45
Q

Where is the caudate and putamen?

A

caudate has head body and tail surrounding thalamus - nucleus accumbens at anterior of the head
Putamen separate from caudate by internal capsule passing between cell bridges

46
Q

Where is the globus pallidus?

A

GPi and GPe are medial to the putamen (thalamus even more medial), look like lens in lateral view

47
Q

Where is the subthalamus?

A

It is in between the globus pallidus and midbrain

48
Q

Where is the substantia nigra?

A

Midbrain

49
Q

What is a corticostriate (CS) loop?

A

motor/cognitive cortical info goes through striatum and globus pallidus
Globus pallidus projects to thalamus which in turn conveys info back to frontal cortex to refine motor and cognitive plan
Substantia nigra and subthalamus modulates loop

50
Q

What is the direct and indirect pathways of the CS loops?

A

Selection of direct pathway - excitatory effects via striatum–/GPi–/Thalamus–>Increased motor output
Indirect pathway - inhibitory effects via striatum–/GPe–/subthalamus–>GPi–/Thalamus–>decreased motor output

51
Q

How does the direct and indirect pathway affect intended movements?

A

Direct path permits intended movements

Indirect path inhibits unintended movements

52
Q

How does DA neuromodulate the striatum?

A

It acts in reinforcing direct and indirect pathways to determine preferred strategies
Persistent reinforcing stimuli (S-R) conditioning permits striatal pathway activity without need for DA, no longer outcome mediated because it’s become habit

53
Q

What receptors do DA use in reinforcing direct and indirect pathways?

A

DA activates direct pathway via D1 type DA receptors
Inhibits indirect pathway via D2 type DA receptors
DA enhances strong inputs; suppresses weak ones
Internally generated behaviors reinforced by DA become habitual

54
Q

Name the four CS loops.

A

Visual
Motivational
Executive
Motor/premotor

55
Q

What parts of the cortex do each of the four CS loops involve?

A

Visual - temporal/ventrolateral prefrontal (externally generated actions)
Motivational - orbitofrontal/anterior cingulate
Executive - dorsolateral prefrontal/posterior parietal
Motor - premotor/SMA/somatosensory (internally generated actions)

56
Q

What are the general functions of each of the four CS loops?

A

They all converge someplace on striatum; motivational loop sends episodic memory to executive loop, which in turn sends input to motor loop for appropriate actions

57
Q

What is declarative memory?

A

Hippocampus-limbic events where episodic memories are stimulus-stimulus associations consolidated into semantic memory in cortex

58
Q

What is emotional memory?

A

Amygdala - emotional conditioning by association of stimulus and aversion

59
Q

What is procedural (non-declarative) memory?

A 
Cerebellum (precise motor) and basal ganglia (habits) - based on associating motor responses with reinforcing stimuli (S-R) to build a repertoire of motor actions
i.e. driving
Unconscious
rigid
procedural
60
Q

What are the three aspects of procedural memory pertaining to the CS loops?

A

Category representation - stimulus from sensory association cortex are linked to appropriate behaviors by clustering similar categories together

Action selection - loops select for desired motor response

Instrumental and reward learning - conditioning behavior to new cognitive or emotional cues reinforced by DA

61
Q

What is declarative learning of visual categories?

A

Declarative - relevant info is maintained over time in working memory, memories are compositional and can be separated, flexible to change memory upon retrieval of new information
Hippocampus, vmPFC, dlPFC

62
Q

What is procedural learning of visual categories?

A

Complex info, associated with behavioral responses, related elements are unified, less flexible
Loop branches to executive and premotor loops, integrate with executive control and working memory

63
Q

What impact does DA neuromodulation have in action selection?

A

Phasic DA activity reinforces specific actions or shifts loops from one action to another depending on feedback from DA system
Forms goal-oriented activity
i.e. learn how to ride a new bike

64
Q

What impact does DA have in instrumental/reward learning?

A

Procedural learning occurs with shift from goal-oriented action (kick) to a stimulus-response (see ball) association, and behavior becomes inflexible, habit
Extinction of inappropriate learned responses uses switching of strategies (DA no longer reinforces pathway)

65
Q

What is instrumental learning?

A

Stages: naive (processing through basal ganglia is undifferentiated)
Appropriate (corticostriatal learning reinforced by DA, task-related elements are sharpened)
Aberrant learning (inappropriate plasticity in the indirect pathway induces inappropriate inhibition and facilitation, task-related elements are noisy)

66
Q

What is reward learning?

A

Goal-oriented behavior subject to motivational state
Associate stimulus with reward rather than motor response based on memories in orbitofrontal and mPFC
Affective experience: sight of food, anticipation that it will be good; taste, smell also cues for reinforcement of behavior

67
Q

What are the characteristics and causes of Huntington’s chorea?

A

Involuntary jerky movements of face, tongue, limbs
Due to lesion of striatum and cortex, causing underactivity of indirect path and facilitating direct path
Loss of striatal GABA neurons that project to GP, AD disease

68
Q

What are the characteristics and causes of athetosis?

A

Writhing limbs

Same loss of striatal GABA neurons seen in chorea

69
Q

What are the characteristics and causes of hemiballismus?

A

Flailing of limbs

Lesion of subthalamus (from virus) reduces inhibitory control over thalamus and cortical output

70
Q

What are the characteristics and causes of Parkinson’s disease?

A

Rest tremor, rigidity, inability to switch strategies, bradykinesia (slow motion)
Due to degeneration of pigmented DA neurons in substantia nigra, less DA to dorsal and ventral striatum

71
Q

What is the imbalance among the limbic regions in schizophrenia?

A

Excess hippocampal activity generates excess tonic levels of DA onto the NAc via ventral pallidum (VTA pathway)
GABA is dysregulated
More tonic DA inhibits PFC input into NAc, more responsive to extraneous stimuli

72
Q

What are the general actions of addictive drugs on the motivational CS loop?

A

Addictive drugs reinforce behavior by increasing DA levels via:
inhibiting uptake or increasing release in the accumbens, inhibiting GABA inhibition in VTA, stimulating nicotinic cholinergic receptors in VT DA cells

DA release leads to neuronal plasticity that may underlie incentive learning and long-term memories associated with cravings in addiction

Organ Systems (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions